The present invention relates to a barrel apparatus for use in treating workpieces with grinding media and, more particularly, to an improvement of such barrel device comprising a hollow barrel provided with a spiral flight on its inner peripheral wall and rotatably supported in horizontal position so as to grind the workpieces placed therein with the grinding media composed of a mixture of grinding particles, lubricating fluid, etc. therein, while being rotated.
Workpiece treating barrels of the prior art, while having a spiral flight on its inner periphery, have had certain defect in that they were designed to scoop up workpieces with the bottom part of the barrel by the action of the spiral flight only and move them forward from one end of the barrel to the other while being tumbled and dropped down onto the bottom part of the barrel during rotation of the barrel, with the result that the workpieces which fell down to the bottom of the barrel tend to deposit and gradually accumulate at the position where they fell, thus without being exposed to the grinding action of the flowing grinding media until the next spiral or band of said flight arrives to pick them up by rotation.
Further drawback of these barrels are that, when the amount of workpieces in the barrel is small or when the finished workpieces are being discharged, the barrel could not satisfactorily deliver them by the pushing action of such spiral flight only, thus causing a small amount of the contents to remain deposited and move back and forth in one pitch of said spiral flight.